After a week's delay because of a compatibility bug in the point-of-sale software it sells, Microsoft has released Windows XP Service Pack 3 (SP3) to the general public.

Windows XP users who manually called up Windows Update early Tuesday afternoon, Eastern time, found SP3 waiting. "Windows XP SP3 contains a small number of new updates and should not significantly change the Windows XP experience," the Windows Update message read in part. "After you install this item, you may have to restart your computer."

Microsoft estimated the Windows Update download as approximately 67MB in size.

The company also posted a 316MB stand-alone installer on its download site and recommended it to users updating multiple machines. An even larger .iso, or disk image, file has also been added to Microsoft's Download Center; the disk image tipped the scales at 545MB.

A week ago, on the day Microsoft had originally slated to post XP SP3 on Windows Update, the company announced that it was postponing the rollout because it had uncovered a flaw that caused its retail point-of-sale software, Microsoft Dynamics Retail Management System (RMS), to lose or corrupt data when used on either Windows XP SP3 or Windows Vista SP1.

Microsoft has a fix for the RMS bug, but hasn't yet put it into wide distribution. A support document noted that a hotfix is ready, but told RMS users to contact Microsoft for the patch. Meanwhile, a company spokeswoman said in an e-mail that Microsoft would make the fix generally available "over the next month." Until then, she continued, Microsoft is telling RMS customers not to install XP SP3.

The company has also added filters to Windows Update so that machines running RMS will not be offered Windows XP SP3, the spokeswoman said.

Microsoft will eventually push XP SP3 to users who have set Windows Update to automatically download and install important updates, but it has not nailed down a date for doing so. So far, company representatives, including XP SP3 release manager Chris Keroack, have said only that it would happen sometime in "early summer." Other sources, however, have pegged June 10 as the probable delivery date via automatic download.

Microsoft also said Tuesday that it is resuming automatic distribution of Windows Vista SP1, which it suspended last week at the same time it put the brakes on XP SP3.